Connecting-plug for electrical switchboards.



No. 7o5,|6|. Patented my 22, |902.-

A. T. M. THMsoN.

CUNNECTING PLUG FOR ELECTRICAL SWITCHBOARDS;

(Application flied Dec. 1B, 1899.)

(Il o M o d el.)

UNITED tarn ARTHUR T. M. THOMSON, OF EAS'IVDULWICI'I, ENGLAND.

CONNECTING-'PLUG FOR ELECTRICAL SWITCHBOARUS.

SPECIFICATION forming part of Letters ltatent No. 705,161, dated July 22, 1902. Application filed December 18,- 1899. Serial No. 740,804. (No model.)

To all whom, t may concern:

Be it known that I, ARTHUR TrroMAs Mln NOR THOMSON, of No. 5l Beauval road, East Dulwich, in the county of Surrey, England, have invented certain new and useful Improvements in Connecting-Plugs for Electrical Switchboards; and I do hereby declare the following to be afull, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to an improved construction of the connecting-plugs for use with electrical switchboards by providing in the end of the plug which is outward and in view when the plug is inserted in the jack of the switchboard a small electric lamp the wires of which are so connected with the plug-case andplug-sleeve that the lamp becomes illuminated by a signal-current sent through one of the communication-wires and the casing of the plug.

The igure shown on the annexed drawing, which is a portion of this specification, is a longitudinal section of the plug, the ballpoint (numbered l2) being the end which isinserted in the jack of the switchboard when in use. The other end carries a socket 3, in which is inserted a small electric lamp which is held in place between a transparent or translucent disk 13, which closes the end of the socket 3, and a bush 9. The socket fits over the end of the metal body 5 of the plug, abutting against the shoulder G, and is secured to it by a screw 7. The communciation- Wires are led into the interior of the plug-casing laterally through the aperture between l and 2.

The round small end of the plug-body 5 is the portion which fits the jack of the switchboard, and when inserted is in electric connection with it. Into 5, but insulated from it, is fitted the sleeve 8. A piece at the inner end is secured to this; sleeve by a screw, and by means of the binding-screw ll electric connection with the sleeve may be made inside the plug-casing. Another piece carrying the point l2 of the plug is fitted into the sleeve, but insulated from it, and by means of a binding-screw 14- and two other screws of attachment (shown in the figure) the tip of the plug is placed in electrical connection in the interior of the plug-casing with one of the communication-wires. The second communication-wire is joined up to the sleeve by the binding-screw l1.

Of the two wires of the electric lamp one is joined up to the sleeve of the plug by the binding-screw 1l, and is therefore in permanent electric connection with the second connecting-wire above mentioned, and the other is joined up by a binding-screw l0 to the body of the plug, and is therefore in electric connection with the jack of the switchboard when the plug is inserted. Vith this arrangement a signal-current sent along the second connecting-wire above mentioned and through the casing of the plug will cause the lamp to be illuminated and serve the purpose of a signal.

The transparent or translucent disk 13 may bear a number or other character, which on the illumination of the lamp will become plainly visible and serve to distinguish the plug.

I claim-w- A connecting-plug for an electrical switchboard within the casing of which, at the end projecting from the switchboard, is provided an electric lamp, which is connected by wires, inside the plug, to the casing of the plug and to the sleeve of the plug, which sleeve is also joined to one of the communication-wires of the plug, wherebya signal-current of electricity sent through that wire and the casing of the plug will cause the lamp to be illuminated and serve the purpose of a signal.

In testimony that I claim the foregoing as my invention I have signed my name in presence of two subscribing witnesses.

ARTHUR T. M. THOMSON.

TWitnesses:

WARWICK II. WILLIAMs, WALTER J. SKnnrnN. 

